The currently available multi-band antennas are manufactured by stamping a metal sheet into a desired shape and bending each shaped metal sheet into an antenna; and multiple shaped and bent antennas are then electrically connected to a single piece of circuit board to form a dual-polarized array multi-band antenna structure. Alternatively, the printing technique is used to print a pattern on a copper film of a circuit board for forming an antenna, and the exposure and development technique is used to produce the pattern of the antenna. Thereafter, multiple pieces of circuit boards having the antenna patterns formed thereon are stacked to form a dual-polarized array multi-band antenna structure. The multi-band antenna structure so formed can be used in different bands to receive or transmit signals. Either the stamp formed or the printed conventional multi-band antenna structure is assembled from multiple pieces of antennas to have a relatively large volume and size and requires an increased manufacturing cost. In addition, it is difficult to manufacture and install the conventional multi-band antenna structures because the multiple pieces of antennas have signal feed-in points that are not located on the same plane or at the same position.
To allow simultaneous receiving of signals in multiple bands, it is inevitably the conventional multi-band antenna structures will disadvantageously produce multiple noises when receiving multiple bands of signals. Moreover, the conventional multi-band antenna structures with the three-dimensional configuration tend to vibrate in use, which has an adverse influence on the signal transmission or receiving.
To overcome the above disadvantage, there are antenna manufacturers who try to hold the conventional multi-band antenna structures immovable or protect the same through packaging technology. Basically, the packaging can be performed via injection molding or epoxy potting. However, once the multi-band antenna structure is packaged, it could not be reworked. Therefore, it is a target of persons skilled in the art to improve the conventional multi-band antenna structures.